1. Field of the Invention
Embodiments of the invention relate generally to electronic products and, more specifically but not exclusively relate to electronic products that receive power from external switching power supplies.
2. Background Information
An external power supply is one that remains outside the enclosure of the product, such as the ac adapter for a digital camera, or the dc adapter that allows the product to operate from a power outlet of an automobile. These electronic products usually are small portable units, but products not designed for portability also use external power supplies. For example, some models of small desktop computers use rather large external power supplies.
Manufacturers of electronic products often prefer to use external power supplies rather than an internal power supply to power their equipment. The use of an external power supply reduces the physical size and weight of the product. Also, the design of the product is not burdened with the need to provide cooling for a power supply if the power supply can simply be procured to the manufacturer's specification as an external component. Typically, the external power supply will connect to the product with a long cable to allow the product to be located at a convenient distance away from the power supply.
Manufacturers desire to prevent the use of unauthorized or counterfeit external power supplies with their products. The use of a power supply that does not meet the manufacturer's requirements can expose the product or the user to harm. Manufacturers may also desire to receive information regarding the operating conditions of the external power supply as for example the power consumption of the external power supply or any fault condition that may exist within the external power supply. The ability to receive information regarding the operating conditions of the power supply is also desirable in the case of internal power supplies incorporated inside products such as desktop computers and set top boxes. Internal power supplies are enclosed within the product itself as in the case of products such as set top boxes or TVs. In some cases, a power supply may be fully contained within its own separate enclosure, but yet enclosed inside the enclosure of the product such as a desktop computer.